DE102021104487A1 - Method of operating a vehicle and vehicle - Google Patents

Abstract

The invention is based on a method for operating a vehicle (10), in particular a motor vehicle, the vehicle (10) having a steering system (12) with a steering handle (14), with an actuator unit (1) which is operatively connected to the steering handle (14). 18) and having at least one torque sensor (22) assigned to the actuator unit (18) for detecting a torque signal (24).
It is proposed that a compensation torque (26) correlated with a systematic sensor offset of the torque sensor (22) be determined in a calibration operating state and superimposed in an automated driving operating state to monitor contact with the steering handle (14) with the torque signal (24).

Description

State of the art

The invention is based on a method for operating a vehicle according to the preamble of claim 1 and on a vehicle according to the preamble of claim 10. The invention also relates to a control unit with a computing unit for carrying out such a method.

Vehicles are known from the prior art which have a conventional steering system with a steering handle, for example in the form of a steering wheel, a wheel steering angle adjuster in the form of a steering gear and a steering shaft for mechanically connecting the steering handle to the wheel steering angle adjuster. In addition, vehicles with steer-by-wire steering systems are known, which do not require a direct mechanical connection between a steering handle and steered vehicle wheels and in which a steering input is transmitted to the steering handle exclusively electrically. The latter include an operating unit that can be actuated by a driver and at least one wheel steering angle adjuster that is mechanically separate from the operating unit. In both cases, steering systems of this type also include at least one actuator unit which, in a normal operating state, is controlled using a torque signal from a torque sensor. The actuator unit can be provided to provide a steering torque, for example in the form of a support torque, and/or to generate a steering resistance and/or a restoring torque on the steering handle. Such a steering system is, for example, from DE 10 2008 037 870 B4 and/or the DE 10 2018 123 615 A1 known.

The torque sensors used are also safety-critical components that must be calibrated and/or adjusted with particular precision in order to avoid errors in the torque signal during driving, as these can lead to uncontrolled movement of the steering handle, to lane deviations in automated driving and /or can lead to an incorrectly recognized touch of the steering handle in automated driving mode. In this context, system-immanent deviations as well as aging and wear effects of the torque sensor must be taken into account.

Proceeding from this, the object of the invention is in particular to provide a method for operating a vehicle and a vehicle with improved properties in terms of operational safety and/or functionality. The object is achieved by the features of claims 1, 9 and 10, while advantageous configurations and developments of the invention can be found in the dependent claims.

Disclosure of Invention

The invention is based on a method for operating a vehicle, in particular a motor vehicle, the vehicle comprising a steering system with a steering handle, with an actuator unit which is operatively connected to the steering handle and with at least one torque sensor assigned to the actuator unit for detecting a torque signal.

It is proposed that a compensation torque correlated with a systematic sensor offset of the torque sensor is determined in a calibration operating state and superimposed on the torque signal in an automated driving operating state to monitor contact with the steering handle. In the present case, the compensation torque is thus determined in the calibration operating state. In addition, the compensating torque in the automated driving mode is superimposed with the torque signal in order to obtain a corrected torque signal, with the corrected torque signal being evaluated to determine whether or not the steering handle is and/or is being touched (so-called hands-on detection or hands-off detection). With this configuration, operational reliability can be increased and/or functionality can be improved. In particular, a particularly precisely calibrated and/or adjusted torque sensor can be provided, which advantageously prevents incorrectly identified contact with the steering handle during automated driving and/or an impermissible release of the steering handle during automated driving can be reliably detected. Advantageously, an impermissible release of the steering handle during automated driving operation can be recognized and the driver can be warned and/or the vehicle can be brought into a safe state.

The steering system can be designed in particular as a conventional steering system, in particular as an electric power steering system, and can include mechanical penetration. In this case, the actuator unit can be designed as a steering actuator to support a manual torque applied to the steering handle. However, the steering system is preferably designed as a steer-by-wire steering system and comprises in particular an operating unit and at least one wheel steering angle adjuster which is mechanically separate from the operating unit and which is used to change a wheel steering angle of at least one vehicle wheel as a function a steering specification is provided. In this case, the actuator unit is preferably part of the operating unit and mechanically coupled to the steering handle. The actuator unit is particularly preferably designed as a feedback actuator for generating a steering resistance and/or a restoring torque on the steering handle. In addition, the actuator unit is advantageously designed as an electrical three-phase machine, in particular as a synchronous machine and particularly preferably as a permanently excited synchronous machine, and is preferably controlled in a normal operating state by a controller unit using the torque signal of the torque sensor. The controller unit is intended in particular to provide a control functionality for operating the actuator unit and consequently for controlling a movement of the steering handle and/or for adjusting a steering feel. The torque signal of the torque sensor advantageously serves as the feedback variable. The regulator unit is preferably also integrated into a control unit of the vehicle, advantageously a control unit designed as a steering control unit.

In addition, a "systematic sensor offset" is to be understood in particular as an offset error of the torque sensor, in particular in a rest position, and/or a, in particular systematic, deviation from a defined zero position and/or a defined zero point of the torque sensor, in particular in a rest position. The systematic sensor offset is caused in particular by the nature of the torque sensor and can include, for example, an initial offset, a system-inherent offset, an offset caused by aging and/or wear effects, an offset caused by internal friction effects and/or a temperature-related offset. Furthermore, a “calibration operating state” should be understood to mean an operating state, in particular during operation of the steering system and consequently of the torque sensor in the vehicle, in which the compensation torque is determined. In particular, at least one value of the compensation torque is determined for at least one defined deflection position of the steering handle. In the calibration operating state, however, multiple values of the compensation torque are preferably determined for multiple, different deflection positions of the steering handle. The calibration operating state and consequently the determination of the compensation torque could be carried out in particular in a further driving operating state, for example during further automated driving of the vehicle. However, the calibration operating state and consequently the determination of the compensation torque are preferably carried out when the vehicle is stationary and particularly preferably in a special service operating mode.

Furthermore, the vehicle includes at least one computing unit, which is provided to carry out the method for operating the vehicle. A “processing unit” is to be understood in particular as an electrical and/or electronic unit which has an information input, an information processing and an information output. The computing unit also advantageously has at least one processor, at least one operating memory, at least one input and/or output means, at least one operating program, at least one control routine, at least one regulation routine, at least one determination routine and/or at least one monitoring routine. In particular, the arithmetic unit is provided in the calibration operating state to determine a compensation torque that is correlated with a systematic sensor offset of the torque sensor. In addition, the computing unit is provided in the automated driving mode at least to superimpose and evaluate the compensating torque for monitoring contact with the steering handle with the torque signal. In addition, the computing unit can be provided for initializing and/or for determining the calibration operating state. The computing unit is preferably also integrated into a control unit of the vehicle, advantageously a control unit designed as a steering control unit. “Provided” should be understood to mean, in particular, specially programmed, designed and/or equipped. The fact that an object is provided for a specific function is to be understood in particular to mean that the object fulfills and/or executes this specific function in at least one application and/or operating state.

Advantageously, it is also proposed that the torque signal and the compensating torque are superimposed in the automated driving mode in order to generate a corrected torque signal, and the corrected torque signal is supplied to a control observer to monitor contact with the steering handle. In this way, particularly simple and/or efficient monitoring can be achieved.

It is also proposed that the compensation torque is determined in the calibration operating state at a time and/or in a state in which the steering handle is not and/or is not being touched, in particular a so-called hands-off state. As a result, the compensation moment can advantageously be precise and can be determined independently of external influences.

In order to determine the compensation torque, an oscillation torque could be applied to the steering handle in the calibration operating state, for example by means of the actuator unit and/or an, in particular additional, oscillation unit. Advantageously, however, it is proposed that, in order to determine the compensation torque in the calibration operating state, an oscillation is generated in the torque signal, in particular in the form of a damped oscillation, in that the steering handle is deflected by activation of the actuator unit and a movement of the steering handle is stopped abruptly when a predefined deflection position is reached is, in particular by braking the actuator unit. In this case, the actuator unit, the torque sensor and the steering handle act as an oscillating circuit and accordingly ensure that the forced oscillation triggered by the actuator unit is damped. The compensation torque can then advantageously be determined or read off in the steady state. Due to the forced oscillation triggered by the actuator unit, the compensation torque for a defined deflection of the steering handle can advantageously be determined easily and in particular in the vehicle.

In principle, exactly one value of the compensation torque could be determined for exactly one defined deflection position of the steering handle. In this context it is conceivable, for example, to determine a maximum value of the compensation torque or a mean value of the compensation torque and to use it to monitor contact with the steering handle. However, particularly precise monitoring, in particular for a large number of deflections of the steering handle, can be achieved if the compensation torque is determined in the calibration operating state for a number of different deflection positions of the steering handle and varies in the automated driving operating state depending on a current deflection position of the steering handle and/or is adjusted. In the calibration operating state, an oscillation is preferably generated in the torque signal for the different deflection positions, in that the steering handle is deflected by activation of the actuator unit and a movement of the steering handle is stopped abruptly when the respective deflection position is reached, with the corresponding value for the compensation torque together with the corresponding deflection position is stored. In the automated driving mode, a current deflection position is then preferably determined and, depending on the current deflection position, a value for the compensation torque that is correlated with the current deflection position is determined and/or read out, which is then overlaid with the torque signal. The compensation torque is particularly advantageously determined for at least four, advantageously for at least ten and particularly preferably for at least twenty, different deflection positions of the steering handle and correspondingly varied and/or adjusted in the automated driving mode.

Furthermore, it is proposed that in the event that there is no compensation torque for a defined deflection position in the automated driving mode, a value of the compensation torque is used for a next larger deflection position of the steering handle or a next smaller deflection position of the steering handle. In this way, in particular, a calibration effort can be minimized and at the same time a particularly resource-saving method can be provided. Alternatively, however, it is also conceivable to determine a value for the corresponding compensation torque by means of interpolation if a value of the compensation torque is missing for a defined deflection position.

In a preferred embodiment, it is also proposed that the corresponding deflection position be stored in a table of values together with the value for the compensating torque and that the compensating torque in the automated driving mode be retrieved from the table of values and/or read out depending on the current deflection position of the steering handle. As a result, a particularly rapid adjustment of the compensation torque to different deflections of the steering handle can be achieved.

It is also proposed that the calibration operating state be repeated at regular time intervals, for example each time the system is started or annually or every two years, such as in particular at a motor vehicle inspection and/or customer service appointment. In this way, the effects of aging and wear on the torque sensor can advantageously be taken into account and compensated for.

Here, the method for operating the vehicle and the vehicle should not be limited to the application and embodiment described above. In particular, the method for operating the vehicle and the vehicle for fulfilling a functionality described herein can be one of a number mentioned herein have different numbers of individual elements, components and units.

character list

Further advantages result from the following description of the drawings. In the drawings an embodiment of the invention is shown.

• 1a-b ein Fahrzeug mit einem beispielhaft als Steer-by-Wire-Lenksystem ausgebildeten Lenksystem in einer vereinfachten Darstellung,
• 2 ein Blockdiagramm eines Regelkreises des Lenksystems,
• 3a-c beispielhafte Schaubilder verschiedener Signale zur Ermittlung eines Kompensationsmoments in einem Kalibrierungsbetriebszustand und
• 4 ein beispielhaftes Ablaufdiagramm mit Hauptverfahrensschritten eines Verfahrens zum Betrieb des Fahrzeugs.

Show it:

• 1a-b a vehicle with a steering system designed as an example as a steer-by-wire steering system in a simplified representation,
• 2 a block diagram of a control circuit of the steering system,
• 3a-c exemplary diagrams of various signals for determining a compensation torque in a calibration operating state and
• 4 an exemplary flowchart with main method steps of a method for operating the vehicle.

Description of the embodiment

the 1a and 1b show a vehicle 10 designed as an example as a passenger vehicle with a plurality of vehicle wheels 32 and with a steering system 12 in a simplified representation. In the present case, vehicle 10 includes a manual driving mode and at least one automated driving mode. The steering system 12 has an operative connection with the vehicle wheels 32 and is provided for influencing a direction of travel of the vehicle 10 . Furthermore, the steering system 12 is designed as a steer-by-wire steering system in the present case, in which a steering specification is electrically forwarded to the vehicle wheels 32 in at least one operating state. In principle, however, a steering system could also be designed as a conventional steering system, in particular as an electric power steering system.

The steering system 12 has a wheel steering angle adjuster 34 known per se. The wheel steering angle adjuster 34 is designed as a central adjuster, for example. The wheel steering angle adjuster 34 has an operative connection with at least two of the vehicle wheels 32, in particular two front wheels, and is intended to convert the steering specification into a steering movement of the vehicle wheels 32. For this purpose, wheel steering angle adjuster 34 includes a steering control element 36, embodied, for example, as a toothed rack, and an actuator unit 38 that interacts with steering control element 36. Actuator unit 38 is embodied as a steering actuator, in particular as an electric motor, and is provided for controlling steerable vehicle wheels 32. In principle, a steering system could of course also include a plurality of wheel steering angle adjusters, in particular designed as individual wheel adjusters. Furthermore, an actuator unit could include multiple electric motors. In addition, a wheel steering angle adjuster could in principle also be designed as a conventional steering gear and mechanically connected to a steering handle via a steering shaft.

In addition, the steering system 12 has an operating unit 40 that can be actuated in particular by a driver and/or occupants. The operating unit 40 is mechanically separate from the wheel steering angle adjuster 34 . The operating unit 40 is purely electrically connected to the wheel steering angle adjuster 34 . Operating unit 40 includes a steering handle 14, for example in the form of a steering wheel, and a further actuator unit 18, in particular mechanically coupled to steering handle 14. Further actuator unit 18 is designed as a feedback actuator and is used at least to generate a steering resistance and/or a restoring torque provided on the steering handle 14. For this purpose, the further actuator unit 18 comprises at least one electric motor (not shown), in particular designed as a permanently excited synchronous motor. In addition, the operating unit 40 includes at least one torsion element 42, in the present case in particular a torsion bar, which is provided for a rotation depending on a movement of the steering handle 14. Alternatively, a steering handle could also be designed as a joystick, as a steering lever and/or as a steering ball or the like. Furthermore, a further actuator unit could also include several electric motors. In addition, it is conceivable to connect an operating unit and a wheel steering angle adjuster to one another by means of a steering shaft, such as in a conventional steering system.

Furthermore, the steering system 12 comprises at least one torque sensor 22. In the present case, the torque sensor 22 is part of the operating unit 40 and is arranged in particular in the region of the torsion element 42. The torque sensor 22 is assigned to the further actuator unit 18 . The torque sensor 22 is provided to detect a torque signal 24 correlated with a twisting of the torsion element 42 . In principle, however, a torque sensor could also be designed separately from an operating unit, such as in a conventional steering system.

In addition, the vehicle 10 has a control device 28 . In the present case, control unit 28 is embodied as a central steering control unit and is therefore part of steering system 12 . Control unit 28 has an electrical connection to wheel steering angle adjuster 34 . That Control unit 28 also has an electrical connection to operating unit 40 . The control device 28 is provided for controlling an operation of the steering system 12 . In the present case, control unit 28 is provided to activate actuator unit 38 as a function of a signal from operating unit 40, for example as a function of a steering specification and/or a manual torque. The control unit 28 is also provided to control the further actuator unit 18 as a function of a signal from the wheel steering angle adjuster 34 .

For this purpose, the control unit 28 includes a computing unit 30. The computing unit 30 includes at least one processor (not shown), for example in the form of a microprocessor, and at least one operating memory (not shown). In addition, the arithmetic unit 30 includes at least one operating program stored in the operating memory with at least one control routine, at least one regulating routine, at least one determination routine and at least one compensation routine. In principle, however, a vehicle could also include a plurality of control units, with a first control unit having at least one first processing unit being assigned to an operating unit, while a second control unit having at least one second processing unit being assigned to a wheel steering angle adjuster. In this case, the first control device and the second control device could communicate electrically with one another. Furthermore, a control unit could also be different from a steering system and be designed, for example, as the central control unit of a vehicle.

2 shows a simplified, schematic structure of a part of the control unit 28 and in particular a simplified basic block diagram of a control circuit for the further actuator unit 18. In the present case, the steering system 12 has a control circuit 16. The control circuit 16 is operatively connected to the steering handle 14 and serves in particular to control a movement of the steering handle 14 and/or to adapt a steering feel that can be perceived on the steering handle 14 .

The control circuit 16 includes the additional actuator unit 18 and the torque sensor 22, with the torque signal 24 of the torque sensor 22 serving as a feedback variable. In addition, the control circuit 16 includes an electrical and/or electronic controller unit 20 for controlling the further actuator unit 18. The controller unit 20 is integrated into the control unit 28 and has an electrical connection to the computing unit 30. Furthermore, the controller unit 20 is designed as a torque controller, in the present case in particular as a state controller. In addition, the control circuit 16 includes a steering feel module 44 in the present case. The steering feel module 44 is integrated into the control unit 28 and has an electrical connection to the processing unit 30 . The steering feel module 44 is provided to provide a setpoint specification 48 for a steering feel that can be perceived in particular on the steering handle 14 and to supply it to the controller unit 20 as a reference variable. Alternatively, however, it is also conceivable to dispense with a steering feel module entirely. Furthermore, a functionality of a steering feel module and/or a controller unit could also be integrated into a computing unit. In addition, it is conceivable to dispense with a control circuit entirely.

The torque sensor 22 used is a safety-critical component. Accordingly, the torque sensor 22 must be calibrated and/or adjusted particularly precisely in order to avoid errors in the torque signal 24 during driving operation. However, such torque sensors can have a systematic sensor offset, which is caused by the nature of the respective torque sensor and can include, for example, an inherent system offset and/or an offset caused by aging and/or wear effects. The sensor offset means that in what is known as a hands-off state, in which a system deviation should actually disappear and consequently the further actuator unit 18 should not be activated, there is a system deviation not equal to zero. A triggering of the further actuator unit 18 triggered by this can then lead to an uncontrolled movement of the steering handle 14 and thus to an incorrectly recognized touching of the steering handle 14 and/or an incorrectly recognized release in automated driving.

In order to increase operational reliability and/or improve functionality, a method for operating the vehicle is proposed below. In the present case, the arithmetic unit 30 is provided in particular to carry out the method and for this purpose has in particular a computer program with corresponding program code means. Alternatively, however, a first computing unit of a first control unit, assigned to an operating unit, could also be provided for carrying out the method.

In the present case, a compensation torque 26 correlated with a systematic sensor offset of the torque sensor 22 is determined in a calibration operating state. In addition, determined compensation torque 26 is superimposed on torque signal 24 and evaluated in an automated driving mode to monitor contact with steering handle 14 . In addition, the calculated compen sationsmoment 26 fed to the reduction and in particular to compensate for the systematic sensor offset of the torque sensor 22 in the control circuit 16 and with at least one signal of the control circuit 16, advantageously the torque signal 24, offset. In principle, however, such a compensation of the systematic sensor offset of the torque sensor 22 could also be dispensed with.

The calibration operating state is carried out during operation of the steering system 12 and consequently of the torque sensor 22 in the vehicle 10, preferably when the vehicle 10 is stationary Vehicle 10 or can be activated by a service employee, for example by means of an on-board computer. Furthermore, the compensation torque 26 is determined at a point in time and/or in a state in which the steering handle 14 is not and/or is not being touched, in particular a so-called hands-off state. In principle, the calibration operating state can be repeated at regular time intervals or depending on the situation, ie if necessary. In principle, however, a calibration operating state could also be carried out in a further driving operating state, for example during automated driving.

In the present case, to determine the compensation torque 26 in the calibration operating state, an oscillation is generated in the torque signal 24 in that the steering handle 14 is deflected by activation of the further actuator unit 18 and a movement of the steering handle 14 is abruptly stopped when a predefined deflection position is reached by braking the further actuator unit 18 becomes. In this case, the further actuator unit 18, the torque sensor 22 and the steering handle 14 act as an oscillating circuit and accordingly ensure that the forced oscillation triggered by the further actuator unit 18 is damped. The compensation torque 26 can then be determined or read off in the steady state. In this context, use is made of the fact that the forced oscillation can eliminate a system-immanent hysteresis in torque sensor 22, which is caused in particular by internal friction of torque sensor 22 and a resulting deviation from a zero position and/or a zero point. By contrast, due to the oscillation in the form of the damped oscillation, the torque sensor 22 or the torque signal 24 moves around the actual zero position and/or the actual zero point and finally levels off at the actual zero. In principle, a similar effect results as with the demagnetization of a permanent magnet by means of an alternating magnetic field. The compensation torque 26 can then be determined on the basis of the actual zero position and/or the actual zero point. Alternatively, however, it is also conceivable to apply an oscillating moment to a steering handle by means of an actuator unit and/or an, in particular additional, oscillating unit and thereby generate a forced oscillation.

In addition, the compensation torque 26 is determined in the calibration operating state for a number of different deflection positions of the steering handle 14 . For this purpose, an oscillation is generated in the torque signal 24 for the different deflection positions in that the steering handle 14 is deflected by activation of the further actuator unit 18 and a movement of the steering handle 14 is stopped abruptly when the respective deflection position is reached. The corresponding value for the compensating torque 26 is then stored together with the corresponding deflection position and preferably stored in a memory unit 46, in particular a non-volatile memory unit, preferably in the form of a table of values. In the present case, the compensating moment 26 is determined for at least twenty-five different deflection positions of the steering handle 14 . In principle, however, exactly one value of a compensation torque, for example a maximum value, could also be determined for exactly one defined deflection position of a steering handle.

In the automated driving mode, the torque signal 24 is superimposed on the compensation torque 26 determined in particular in the calibration mode in order to generate a corrected torque signal 50 . The corrected torque signal 50 can then be supplied to an observer 72 to monitor the contact with the steering handle 14, it being determined by evaluating the corrected torque signal 50 whether the steering handle 14 is and/or is being touched or not (so-called hands-on detection or .Hands-off detection). Observer 72 is in the form of a control engineering observer and is operatively connected to control circuit 16 in the present case. In addition, observer 72 is integrated into control unit 28 and has an electrical connection to computing unit 30 .

In addition, the compensation torque 26 can be supplied to the control circuit 16 and with it at least one signal of the control circuit 16 are offset. In the present case, the torque signal 24 is superimposed with the compensation torque 26 in order to generate the corrected torque signal 50 . The corrected torque signal 50 can then additionally be used to reduce and in particular to compensate for the systematic sensor offset of the torque sensor 22 with the setpoint specification 48 of the controller unit 20 or fed directly to the controller unit 20 as an input variable. In principle, however, such a compensation of the systematic sensor offset of the torque sensor 22 could also be dispensed with.

In addition, the compensation torque 26 is varied and/or adjusted in the automated driving mode as a function of a current deflection position 52 of the steering handle 14 . For this purpose, a current deflection position 52 of the steering handle 14 is first determined and a value of the compensation torque 26 assigned to the current deflection position 52 is determined. Subsequently, the compensating torque 26 is retrieved and/or read out from the storage unit 46 and in particular the value table as a function of the current deflection position 52 of the steering handle 14 and the torque signal 24 is superimposed. If a value of the compensating torque 26 is missing for a defined deflection position, a value of the compensating torque 26 is used for a next larger deflection position of the steering handle 14 or a next smaller deflection position of the steering handle 14 . Alternatively, however, missing values could also be determined by means of an interpolation.

the 3a until 3c show exemplary diagrams of various signals for determining the compensation torque 26 in the calibration operating state.

In 3a a torque in [Nm] is plotted on an ordinate axis 54 . A time in [s] is shown on an abscissa axis 56 . A curve 58 shows a course of the torque signal 24 in the calibration operating state.

The course of the torque signal 24 shows that a system-immanent hysteresis in the torque sensor 22 can be eliminated by the forced oscillation. Due to the oscillation in the form of the damped oscillation, the torque sensor 22 or the torque signal 24 moves around the actual zero position and/or the actual zero point and finally levels off at the actual zero.

In 3b the sensor offset of the torque sensor 22 is plotted in [Nm] on an ordinate axis 60 . A deflection of the steering handle 14, present in particular in the form of a steering angle, is shown in [°] on an abscissa axis 62. A group of points 64 shows a course of the sensor offset of the torque sensor 22 for several different deflection positions of the steering handle 14.

The course of the sensor offset of the torque sensor 22 shows that the sensor offset fluctuates depending on the deflection positions of the steering handle 14 . In order to implement a particularly precise monitoring function, the compensation torque 26 is therefore advantageously determined for a large number of different deflection positions of the steering handle 14 .

In 3c a deflection of the steering handle 14, present in particular in the form of a steering angle, is plotted in [°] on an ordinate axis 66. A time in [s] is shown on an abscissa axis 68 . A curve 70 visualizes the method for determining the compensation torque 26 in the calibration operating state, with an oscillation being generated in the torque signal 24 by the steering handle 14 being deflected by activation of the further actuator unit 18 and a movement of the steering handle 14 when a respective deflection position is reached by braking the further actuator unit 18 is stopped abruptly. This results in the in 3c shown stepped course of the curve 70.

4 Finally, FIG. 1 shows an exemplary flow chart with main method steps of the method for operating the vehicle 10.

A method step 80 corresponds to a calibration operating state in which the compensation torque 26 correlated with the systematic sensor offset of the torque sensor 22 is determined. First, a service operating mode is activated and then, to determine the compensation torque 26, an oscillation is generated in the torque signal 24 in that the steering handle 14 is deflected by activation of the additional actuator unit 18 and a movement of the steering handle 14 when a predefined deflection position is reached by braking the additional actuator unit 18 is stopped abruptly. In addition, the determination of the compensation torque 26 can be repeated for several different deflection positions of the steering handle 14 .

A step 82 corresponds to an automated driving mode in which the compensating torque 26 is superimposed on the torque signal 24 to monitor contact with the steering handle 14 and is evaluated. For this purpose, the torque signal 24 and the compensation torque 26 are superimposed on one another and fed to the observer 72 . In addition, the compensation torque 26 is varied and/or adjusted as a function of a current deflection position 52 of the steering handle 14 .

The example flowchart in 4 is intended to describe a method for operating the vehicle 10 by way of example only. In particular, individual process steps can also vary or additional process steps can be added. In this context, it is conceivable, for example, to apply an oscillating torque to a steering handle by means of an actuator unit and/or an oscillation unit, in particular an additional one, and thereby generate a forced oscillation and/or exactly one value of a compensation torque, for example a maximum value, for exactly one defined To determine deflection position of a steering handle. Furthermore, varying and/or adjusting a compensation torque as a function of a current deflection position of a steering handle could also be dispensed with. In addition, the method could also be used analogously in a conventional steering system, in particular an electric power steering system, in which case a steering actuator is used as the actuator unit to support a manual torque applied to a steering handle.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102008037870 B4 [0002]
• DE 102018123615 A1 [0002]

Claims (13)

Method for operating a vehicle (10), in particular a motor vehicle, the vehicle (10) having a steering system (12) with a steering handle (14), with an actuator unit (18) which is operatively connected to the steering handle (14) and with at least one comprises the torque sensor (22) assigned to the actuator unit (18) for detecting a torque signal (24), characterized in that a compensation torque (26) correlated with a systematic sensor offset of the torque sensor (22) is determined in a calibration operating state and in an automated driving operating state for monitoring a Touching the steering handle (14) with the torque signal (24) is superimposed. procedure after claim 1 , characterized in that the torque signal (24) and the compensation torque (26) are superimposed in the automated driving mode in order to generate a corrected torque signal (50), and the corrected torque signal (50) for monitoring contact with the steering handle (14). Observer (72) is supplied. procedure after claim 1 or 2 , characterized in that the compensation torque (26) is determined in the calibration operating state at a time in which no contact with the steering handle (14) takes place and / or takes place, in particular a so-called hands-off state. Method according to one of the preceding claims, characterized in that to determine the compensation torque (26) in the calibration operating state, an oscillation is generated in the torque signal (24) by the steering handle (14) being deflected by activation of the actuator unit (18) and a movement the steering handle (14) is stopped abruptly when a predefined deflection position is reached. Method according to one of the preceding claims, characterized in that the compensation torque (26) is determined in the calibration operating state for a plurality of different deflection positions of the steering handle (14) and in the automated driving operating state depending on a current deflection position (52) of the steering handle (14) varies becomes. procedure after claim 5 , characterized in that if there is no compensation torque for a defined deflection position in the automated driving mode, a value of the compensation torque (26) is used for a next larger deflection position of the steering handle (14) or a next smaller deflection position of the steering handle (14). . procedure after claim 5 or 6 , characterized in that the corresponding deflection position together with the value for the compensation torque (26) are stored in a value table and the compensation torque (26) in the automated driving mode depending on the current deflection position (52) of the steering handle (14) is retrieved from the value table becomes. Method according to one of the preceding claims, characterized in that an execution of the calibration operating state is repeated at regular time intervals. Control device (28) with a computing unit (30) for carrying out a method according to one of the preceding claims. Vehicle (10), in particular a motor vehicle, with a steering system (12), which has a steering handle (14), an actuator unit (18) that is operatively connected to the steering handle (14), and at least one torque sensor (22) assigned to the actuator unit (18) for Detection of a torque signal (24), characterized by a computing unit (30), which is provided to determine a systematic sensor offset of the torque sensor (22) correlated compensation torque (26) in a calibration operating state and in an automated driving operating state to monitor a contact to superimpose the steering handle (14) with the torque signal (24). vehicle after claim 10 , characterized in that the steering system is a conventional electric power steering and the actuator unit is designed as a steering actuator to support a hand torque applied to the steering handle. Vehicle (10) after claim 10 or 11 , characterized in that the steering system (12) is a steer-by-wire steering system and the actuator unit (18) is designed as a feedback actuator for generating a steering resistance and/or a restoring moment on the steering handle (14). Vehicle (10) according to one of Claims 10 until 12 , characterized in that the computing unit (30) for carrying out a procedural rens after one of the Claims 1 until 8th is provided.

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